The present invention relates in general to the field of the process technology of cleaning plants, and in particular to mobile cleaning systems for shopping trolleys consisting of a plurality of cleaning stations, a new circulatory type of arrangement of the individual stations being used in order to obtain processing advantages and therefore increased economic efficiency of the entire cleaning system.
The term “shopping trolleys” as used below refers to transport containers which today are principally used in large shops, grocery stores and supermarkets in order to facilitate for customers the transportation of goods selected in the store to the cash till and optionally the transportation of the goods purchased at the till to a transport vehicle parked in front of the store. Because of their frequent use and as a result of residues of products left behind as refuse in the trolleys, said trolleys become soiled within a short time so that it is necessary for hygienic and health reasons to subject used shopping trolleys to thorough cleaning at regular intervals in order to meet food hygiene regulations.
The invention relates equally to the cleaning of comparable transport devices such as boxes, crates and other containers.
Whereas earlier shopping trolleys had to be scrubbed and washed manually using chemical cleaning agents, fully automatic cleaning plants, which carry out the cleaning process considerably more efficiently and therefore represent a major facilitation, are increasingly used today. In addition, when using fully automatic cleaning plants, a large proportion of the cleaning personnel employed at the store can be saved.
Because the shopping trolleys of different stores which are to be cleaned are located at different sites and must be cleaned on site, it is necessary that the automatic cleaning plant can be transported to the place of use.
Conventional mobile cleaning and washing plants for shopping trolleys of all kinds generally comprise at least one cleaning station, a water treatment plant having pumps, valves, filters, pipework, containers and/or measuring instruments, a control unit, a housing in which the components listed are installed and a transport device on which the housing is mounted.
According to the prior art, various solutions to the problem of the automatic cleaning of trolleys are available, each of these solutions being optimised for a particular application. Certain limitations are therefore associated with each of these solutions. To explain in general terms some of the most important of these solutions, it is necessary to refer briefly to their most important aspects.
The invention proposed in German Patent DE 198 57 915 A1 relates to a mobile cleaning and washing plant for shopping trolleys of all kinds in which a washing box together with a cleaning fluid or water treatment plant and connecting pipes is mounted on a base frame which in turn is attached to a transport device. To clean the shopping trolleys, the mobile cleaning and washing plant, when at the desired place of use, is either placed on the supports of the base frame in front of the transport device, or remains on the transport device during the cleaning operation.
In the German Utility Model Application DE 298 12 683 U1, a mobile washing container is disclosed which can be used in particular for cleaning shopping trolleys, mesh boxes and merchandise baskets. This mobile washing container is a standard Eurocontainer. After the residual waste has been conveyed into a collecting tray by means of a suction fan, the transport containers to be cleaned are moved through a washing installation which includes high-pressure jets, movable and adjustable washing brushes, disinfectant jets, a drying-air duct and an oil spray device for spraying the wheels and wheel pivots of the transport containers to be cleaned. Spraying of the transport containers to be cleaned with a disinfectant by means of disinfectant jets specially provided for this purpose ensures additional hygiene. A recirculated water cleaning arrangement which carries out a water treatment process is also integrated in the mobile washing container. Because it has an independent power supply, this washing container can be used everywhere without being dependent on external power supply arrangements.
German Utility Model Application DE 299 01 282 U1 relates to a washing system for shopping trolleys which is equipped with its own power supply unit. This can be preferably a diesel unit which generates electric current in order to operate the electrical, pneumatic and hydraulic components contained in the washing system disclosed. The washing system also includes a purification component which purifies the used cleaning fluid so that said fluid needs to be changed less frequently. In addition, a blast air drying system is integrated to dry the shopping trolleys after washing. The washing system also includes components which lubricate the wheels and wheel axles.
German Patent Application DE 38 28 035 C2 discloses a machine which can be placed directly on the ground for cleaning serving trolleys, aircraft catering trolleys, kitchen trolleys or suchlike transport vehicles for groceries in which the vehicles are fed to the cleaning machine manually via a ramp, then automatically opened, pre-washed and washed, rinsed, dried and removed again manually via a ramp. The cleaning machine comprises successively arranged stations for pre-washing, washing, rinsing and drying the trolleys to be cleaned. Inside the cleaning machine the trolleys are moved through the machine at least between the zones responsible for the washing and drying processes by conveyor means installed in the floor of the cleaning machine. The underlying solution of this patent application is also distinguished by the fact that one or more collecting tanks for receiving cleaning fluid via a suction nozzle and an additional pump are connected to an intermediate tank which in turn is connected via a pressure pump for feeding and/or circulating the cleaning fluid to spraying nozzles which are mounted in both the washing and the rinsing zones.
A mobile cleaning plant for shopping trolleys is disclosed in U.S. Pat. No. 4,807,319. In this system, the shopping trolleys are pushed into the cleaning plant on a long side of the container, transported through the washing installation inside the container by means of a conveyor belt parallel to the longitudinal axis of the container and finally are removed from the container in the cleaned state on the opposite side.
Known from DE 199 36 906 is a cleaning plant for “small containers” in which the objects to be cleaned are conveyed along substantially vertical paths during their passage through the washing installation.